连铸工艺制备多晶硅的热—流模拟

发布时间：2018-03-27 05:35

本文选题：多晶硅　切入点：连铸　出处：《大连理工大学》2015年硕士论文

【摘要】：重要的绿色清洁能源太阳能已经越来越多的受到人们的重视和利用,多晶硅作为最主要的光伏材料,有着巨大的市场需求。利用铸造工艺能够获得较低成本的多晶硅铸锭,并且已得到广泛的应用,但是依然存在着单炉产量小、生产效率低等问题。本文以改进制备工艺、提高铸造法制备多晶硅锭的生产效率为目的,开展了利用连续铸造工艺制备多晶硅铸锭的数值模拟并且结合模拟结果进行初步实验。通过利用有限元铸造模拟软件ProCAST分析了连铸工艺应用于多晶硅铸锭的制备与传统连铸金属材料制备过程的主要异同,根据硅在凝固过程中相对于其他金属材料的特殊物理性质,结合接触应力的模拟结果,提出了多晶硅连铸结晶器内表面锥度的设计原理,并以此为基础设计了一台多晶硅连铸设备。通过对照解析解的计算结果与实际连铸实验测量结果,验证了温度场、流场模拟结果以及热-流耦合计算结果的可靠性。在此基础上对多晶硅连铸工艺包括初始浇注和稳态连铸两个阶段在内的整体连铸过程进行了热-流耦合模拟,得到了连铸不同阶段的温度场分布情况。分析温度场模拟结果发现相对较低的拉坯速度和较小的结晶器换热系数更有益于形成较优质量多晶硅铸锭。结合模拟结果提出的连铸工艺优化方案,利用自主设计的多晶硅连铸设备进行了多晶硅的连铸初步实验,通过合理地控制拉坯速度和结晶器换热,最终利用连铸方法得到了直径为100mm的多晶硅铸锭,通过数值模拟与实际实验相结合的方式,验证了直冷连铸方法运用于多晶硅铸锭制备的可行性。
[Abstract]:The important green clean energy solar energy has been paid more and more attention to and utilized by people. As the most important photovoltaic material, polysilicon has a huge market demand. Low cost polysilicon ingot can be obtained by casting technology. And has been widely used, but there are still some problems such as low production rate and low production efficiency of single furnace. The purpose of this paper is to improve the production efficiency of producing polysilicon ingot by casting. Numerical simulation of polycrystalline silicon ingot prepared by continuous casting process was carried out and preliminary experiment was carried out in combination with simulation results. The continuous casting process was applied to the preparation of polysilicon ingot by using finite element casting simulation software ProCAST. The main similarities and differences between the preparation process of metal materials and conventional continuous casting, According to the special physical properties of silicon relative to other metal materials during solidification and the simulation results of contact stress, the design principle of the inner surface taper of polysilicon continuous casting mould is put forward. Based on this, a polysilicon continuous casting equipment is designed. The temperature field is verified by comparing the calculated results of analytical solution with the measured results of actual continuous casting experiments. Based on the results of flow field simulation and thermal-flow coupled calculation, the thermo-fluid-coupled simulation of the whole continuous casting process including initial casting and steady state continuous casting is carried out. The distribution of temperature field in different stages of continuous casting is obtained. The results of temperature field simulation show that lower casting speed and smaller heat transfer coefficient of mold are more beneficial to the formation of polysilicon ingot with better quality. The optimization scheme of continuous casting process proposed by Guo, The primary experiment of polysilicon continuous casting was carried out by using the self-designed polysilicon continuous casting equipment. By reasonably controlling the casting speed and mold heat transfer, the polycrystalline silicon ingot with diameter of 100mm was obtained by continuous casting method. Through the combination of numerical simulation and practical experiments, the feasibility of applying the method of direct cold continuous casting to the preparation of polysilicon ingot is verified.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ127.2

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